Parameters Affecting the Kinetic Friction of Ice

1987 ◽  
Vol 109 (3) ◽  
pp. 552-559 ◽  
Author(s):  
M. Akkok ◽  
C. M. McC. Ettles ◽  
S. J. Calabrese
Keyword(s):  
Regression Analysis ◽  
Thermal Properties ◽  
Ambient Temperature ◽  
Control Mechanism ◽  
Theoretical Models ◽  
Thermal Control ◽  
Experimental Results ◽  
Analytical Models ◽  
Kinetic Friction ◽  
Ice Friction

A study of the mechanics of ice friction was performed in which various theoretical models were compared to experimental results. Analytical models indicate that ice friction is affected by load, speed, ambient temperature, and thermal properties of the counterface material. All four parameters were varied and the results compared to analytical models with additional study using regression analysis. Conclusions indicate that under some conditions the friction of ice is subject to a thermal control mechanism.

Investigation on the Influence of the Surface Resin Rich Layer on the Thermoelastic Signal from Different Composite Laminate Lay-Ups

2006 ◽  
Vol 3-4 ◽  
pp. 167-172 ◽  
Author(s):  
G. Pitarresi ◽  
A. Conti ◽  
U. Galietti
Keyword(s):  
Composite Laminate ◽  
External Surface ◽  
Theoretical Models ◽  
Experimental Results ◽  
Analytical Models ◽  
Orthotropic Materials ◽  
The Novel ◽  
Thermoelastic Effect ◽  
Significant Difference ◽  
Novel Theory

This work presents a set of experimental results based on the measured thermoelastic signal from GRP composite coupons adopting different lay-ups. A comparison is made with the thermoelastic signal predicted by two different analytical models: one based on the classical law of the thermoelastic effect for orthotropic materials, and the other based on a novel theory accounting for the presence of a resin layer on the external surface of the composite structure. The composite coupons were designed such to determine a significant difference in the predictions made by the two theoretical models. Experimental results have shown a far better match with the predictions based on the novel theory accounting for the presence of a surface resin rich layer.

Thermal Contact Conductance of Non-Flat, Rough, Metallic Coated Metals

2002 ◽  
Vol 124 (3) ◽  
pp. 405-412 ◽  
Author(s):  
M. A. Lambert ◽  
L. S. Fletcher
Keyword(s):  
Empirical Model ◽  
Nuclear Reactor ◽  
Combustion Engine ◽  
Thermal Contact ◽  
Theoretical Models ◽  
Thermal Control ◽  
Experimental Results ◽  
Thermal Contact Conductance ◽  
Contact Conductance ◽  
Semi Empirical

Thermal contact conductance is an important consideration in such applications as nuclear reactor cooling, electronics packaging, spacecraft thermal control, and gas turbine and internal combustion engine cooling. In many instances, the highest possible thermal contact conductance is desired. For this reason, soft, high conductivity, metallic coatings are sometimes applied to contacting surfaces (often metallic) to increase thermal contact conductance. O’Callaghan et al. (1981) as well as Antonetti and Yovanovich (1985, 1988) developed theoretical models for thermal contact conductance of metallic coated metals, both of which have proven accurate for flat, rough surfaces. However, these theories often substantially overpredict the conductance of non-flat, rough, metallic coated metals. In the present investigation, a semi-empirical model for flat and non-flat, rough, uncoated metals, previously developed by Lambert and Fletcher (1996), is employed in predicting the conductance of flat and non-flat, rough, metallic coated metals. The models of Antonetti and Yovanovich (1985, 1988) and Lambert and Fletcher (1996) are compared to experimental data from a number of investigations in the literature. This entailed analyzing the results for a number of metallic coating/substrate combinations on surfaces with widely varying flatness and roughness. Both models agree well with experimental results for flat, rough, metallic coated metals. However, the semi-empirical model by Lambert and Fletcher (1996) is more conservative than the theoretical model by Antonetti and Yovanovich (1985, 1988) when compared to the majority of experimental results for non-flat, rough, metallic coated metals.

scholarly journals Constitutive Models for the Tensile Behaviour of TRM Materials: Literature Review and Experimental Verification

Materials ◽  
2021 ◽  
Vol 14 (3) ◽  
pp. 700
Author(s):  
Maria Concetta Oddo ◽  
Giovanni Minafò ◽  
Lidia La Mendola
Keyword(s):  
State Of The Art ◽  
Constitutive Models ◽  
Stress Transfer ◽  
Theoretical Models ◽  
Tensile Tests ◽  
Analytical Models ◽  
Tensile Behaviour ◽  
Tensile Response ◽  
Textile Reinforced Mortar ◽  
Inorganic Matrix

In recent years, the scientific community has focused its interest on innovative inorganic matrix composite materials, namely TRM (Textile Reinforced Mortar). This class of materials satisfies the need of retrofitting existing masonry buildings, by keeping the compatibility with the substrate. Different recent studies were addressed to improve the knowledge on their mechanical behaviour and some theoretical models were proposed for predicting the tensile response of TRM strips. However, this task is complex due to the heterogeneity of the constituent materials and the stress transfer mechanism developed between matrix and fabric through the interface in the cracked stage. This paper presents a state-of-the-art review on the existing constitutive models for the tensile behavior of TRM composites. Literature experimental results of tensile tests on TRM coupons are presented and compared with the most relevant analytical models proposed until now. Finally, a new experimental study is presented and its results are used to further verify the reliability of the literature expressions.

scholarly journals Intentions versus Outcomes: Cooperation and Fairness in a Sequential Prisoner’s Dilemma with Nature

Games ◽  
2021 ◽  
Vol 12 (3) ◽  
pp. 58
Author(s):  
Garret Ridinger
Keyword(s):  
Perspective Taking ◽  
Prisoner's Dilemma ◽  
Prisoner’S Dilemma ◽  
Theoretical Models ◽  
Empathic Concern ◽  
Experimental Results ◽  
Prisoner’S Dilemma Game ◽  
Psychometric Measures ◽  
Prisoner's Dilemma Game ◽  
First Mover

This paper investigates the importance of concerns about intentions and outcomes in a sequential prisoner’s dilemma game with nature. In the game, there is a chance that the first mover’s choice is reversed. This allows the separation of intended actions from the resulting outcomes. Equilibrium predictions from theoretical models of fairness are tested experimentally by varying the chance the first mover’s choice is reversed and whether the second mover observes the first mover’s choice. The results show that second mover cooperation is higher when the first mover has little control over their choice and when the second mover is not told what the first mover chose. While subject behavior is consistent with concerns for both intentions and outcomes, the results indicate that these concerns work in ways not predicted by current theoretical models. In addition, I find that psychometric measures of empathic concern and perspective taking are correlated with second mover cooperation and provide potential explanations for the experimental results.

scholarly journals Investigating the effects of adding hybrid nanoparticles, graphene and boron nitride nanosheets, to octadecane on its thermal properties

RSC Advances ◽  
2020 ◽  
Vol 10 (25) ◽  
pp. 14785-14793
Author(s):  
Hossein Tafrishi ◽  
Sadegh Sadeghzadeh ◽  
Fatemeh Molaei ◽  
Hossein Siavoshi
Keyword(s):  
Thermal Properties ◽  
Boron Nitride ◽  
Ambient Temperature ◽  
Phase Change ◽  
Phase Change Material ◽  
Thermal Energy ◽  
Hybrid Nanoparticles ◽  
Boron Nitride Nanosheets ◽  
Change Material

Octadecane is an alkane that is used to store thermal energy at ambient temperature as a phase change material.

Design and Fabrication of a Magnetocaloric Microcooler

2005 ◽  
Author(s):  
Sangchae Kim ◽  
Bharath Bethala ◽  
Simone Ghirlanda ◽  
Senthil N. Sambandam ◽  
Shekhar Bhansali
Keyword(s):  
Magnetic Field ◽  
Ambient Temperature ◽  
Temperature Change ◽  
Entropy Change ◽  
Temperature Sensors ◽  
Experimental Results ◽  
Maximum Temperature ◽  
Alternative Technology ◽  
Temperature Conditions ◽  
Si Wafer

Magnetocaloric refrigeration is increasingly being explored as an alternative technology for cooling. This paper presents the design and fabrication of a micromachined magnetocaloric cooler. The cooler consists of fluidic microchannels (in a Si wafer), diffused temperature sensors, and a Gd5(Si2Ge2) magnetocaloric refrigeration element. A magnetic field of 1.5 T is applied using an electromagnet to change the entropy of the magnetocaloric element for different ambient temperature conditions ranging from 258 K to 280 K, and the results are discussed. The tests show a maximum temperature change of 7 K on the magnetocaloric element at 258 K. The experimental results co-relate well with the entropy change of the material.

scholarly journals Comparison of Analytical Approaches Predicting the Compressive Strength of Fibre Reinforced Polymers

Materials ◽  
2018 ◽  
Vol 11 (12) ◽  
pp. 2517 ◽  
Author(s):  
Christian Leopold ◽  
Sergej Harder ◽  
Timo Philipkowski ◽  
Wilfried Liebig ◽  
Bodo Fiedler
Keyword(s):  
Compressive Strength ◽  
Prediction Accuracy ◽  
Volume Fraction ◽  
Fibre Volume Fraction ◽  
Experimental Results ◽  
Analytical Models ◽  
Reinforced Polymers ◽  
Reinforced Polymer ◽  
Fibre Reinforced Polymer ◽  
Analytical Approaches

Common analytical models to predict the unidirectional compressive strength of fibre reinforced polymers are analysed in terms of their accuracy. Several tests were performed to determine parameters for the models and the compressive strength of carbon fibre reinforced polymer (CFRP) and glass fibre reinforced polymer (GFRP). The analytical models are validated for composites with glass and carbon fibres by using the same epoxy matrix system in order to examine whether different fibre types are taken into account. The variation in fibre diameter is smaller for CFRP. The experimental results show that CFRP has about 50% higher compressive strength than GFRP. The models exhibit significantly different results. In general, the analytical models are more precise for CFRP. Only one fibre kinking model’s prediction is in good agreement with the experimental results. This is in contrast to previous findings, where a combined modes model achieves the best prediction accuracy. However, in the original form, the combined modes model is not able to predict the compressive strength for GFRP and was adapted to address this issue. The fibre volume fraction is found to determine the dominating failure mechanisms under compression and thus has a high influence on the prediction accuracy of the various models.

scholarly journals Brazilian gutta-percha points. Part II: thermal properties

2007 ◽  
Vol 21 (1) ◽  
pp. 29-34 ◽  
Author(s):  
Cláudio Maniglia-Ferreira ◽  
Eduardo Diogo Gurgel-Filho ◽  
João Batista Araújo Silva Jr ◽  
Regina Célia Monteiro de Paula ◽  
Judith Pessoa Andrade Feitosa ◽  
...  
Keyword(s):  
Differential Scanning Calorimetry ◽  
Thermal Properties ◽  
Physical Properties ◽  
Ambient Temperature ◽  
Amorphous Phase ◽  
Thermal Behaviour ◽  
Chemical Structure ◽  
Scanning Calorimetry ◽  
Gutta Percha ◽  
Thermal Manipulation

This study was undertaken to explore the effect of heating on gutta-percha, analyzing the occurrence of endothermic peaks corresponding to the transformation that occurs in the crystalline structure of the polymer during thermal manipulation. This study also seeked to determine the temperature at which these peaks occur, causing a transformation from the beta- to the alpha-form, and from the alpha- to the amorphous phase. Eight nonstandardized gutta-percha points commercially available in Brazil (Konne, Tanari, Endopoint, Odous, Dentsply 0.04, Dentsply 0.06, Dentsply TP, Dentsply FM) and pure gutta-percha (control) were analysed using differential scanning calorimetry (DSC) and thermogravimetry analysis (TGA). The transition temperatures were determined and analysed. With the exception of Dentsply 0.04 and Dentsply 0.06, the majority of the products showed thermal behaviour typical of beta-gutta-percha, with two endothermic peaks, exhibiting two crystalline transformations upon heating from ambient temperature to 130°. Upon cooling and reheating, few samples presented two endothermic peaks. It was concluded that heating dental gutta-percha to 130°C causes changes to its chemical structure which permanently alter its physical properties.

scholarly journals Analysis of Hot-Cold Confusion on Fingers

2021 ◽  
Vol 33 (5) ◽  
pp. 1117-1127
Author(s):  
Satoshi Hashiguchi ◽  
Keyword(s):  
Thermal Properties ◽  
Proximal Phalanx ◽  
Mutual Effect ◽  
Distal Phalanx ◽  
Experimental Results ◽  
Middle Phalanx ◽  
Temperature Sensation ◽  
Temperature Stimulus

The thermosensory system may misidentify a temperature stimulus with different thermal properties. The mechanism of this hot-cold confusion has not been clarified; hence, it has not yet been applied. In this study, we created a wearable temperature presentation device that is closer to the application and analyzed the tendency and mechanism of temperature confusion by analyzing the hot-cold confusion of temperature sensation in the fingers, which are most frequently in contact with objects. Two experiments were performed. In the first experiment, we presented stimuli on the tips of three fingers (first, second, and third fingers). In the second experiment, we presented stimuli at the center of the distal phalanx, middle phalanx, and proximal phalanx of the first finger. The experimental results indicated the occurrence of hot-cold confusion. Domination, in which the center is dominated by both ends, and a mutual effect, in which the center interacts with both ends, were observed.

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